Background: A reduction in the salt content of foods such as bread continues to be the main focus for sodium reduction strategies. As mandatory fortification of bread with iodised salt is the main vehicle for iodine fortification in Australia, there is concern that reducing the salt content of bread may adversely affect iodine status.
Aims: To assess i) the relationship between 24-hour urinary sodium (UrNa) and urinary iodine excretion (UIE) and ii) the relationship between bread consumption and UIE in Victorian schoolchildren.
Methods: A cross-sectional study of 5-12 year old Victorian primary school children. Sodium and UIE were assessed using 24-hour urine samples. Bread intake (g/d) was determined via 24-hour dietary recall, completed in a sub-sample of children aged ≥8 years.
Results: Valid 24-hour urine samples were provided by 650 children (n=359 boys, mean(SD) age 9.3(1.8) years) and 448 provided dietary recalls. Mean UrNa and UIE were 104(48) mmol/24hr and 104(54) μg/24hr, respectively. UrNa was positively associated with UIE (r=0.36, P<0.001). In the sub-sample of children with dietary recalls, 86% (n=386) reported consuming bread and mean consumption was 83.6(62.1)g/day. There was no association between bread intake and UIE (r=0.01, P=0.82).
Conclusions: UrNa and UIE were significantly correlated, indicating some common dietary sources of iodine and sodium. No association between bread (containing iodised salt) consumption and UIE was evident in this population, which may indicate a higher contribution of other foods to iodine intake.
Funding Sources: Australian Postgraduate Award, National Heart Foundation of Australia, Helen MacPherson Smith Trust Fund.